HiFonics ZST8D2/D4

The HiFonics ZEUS STREET ZST8 subwoofers combine powerful bass reproduction with an exceptionally slim design. With a shallow installation depth of just 78 mm, these 20 cm (8-inch) subwoofers are ideal for space-saving installations where conventional subwoofers cannot be used due to their height.

A particular challenge with flat subwoofers is the stability of the diaphragm. That’s why HiFonics uses an exceptionally rigid glass-fiber-carbon composite cone in the ZEUS STREET ZST series. This ensures controlled movement even at high excursion levels and reduces unwanted deformation and distortion.

Powerful performance is delivered by a dual-magnet system with a total of 40 ounces of magnetic material, combined with a generously sized 50-mm dual voice coil. The robust design enables a high power handling capacity of 250 watts RMS and up to 500 watts of peak power.

Despite their compact dimensions, the ZST8 subwoofers deliver impressive bass performance. They can already reach their full potential in sealed enclosures with a volume of 9 to 15 liters. Alternatively, they can also be used in a bass-reflex enclosure to achieve greater efficiency in the tuned bass range.

The ZST8D2 and ZST8D4 models differ only in their voice coil impedance and the associated electrical and acoustic parameters.

Features

• 20 cm (8") Slim Subwoofer from the ZEUS STREET Series

• Extremely slim design with an installation depth of just 78 mm

• Highly Durable Glass-Fiber-Carbon Composite Membrane

• Dual-magnet drive with a total of 40 oz (approx. 1.13 kg)

• 50 mm dual voice coil

• Sturdy steel basket with a flat design

• Durable rubber seal

• Nomex centering spider

• Blue Magnetic Protective Cover

• Suitable for sealed and bass-reflex enclosures

• Available in 2 × 2 ohms or 2 × 4 ohms

Technical Specifications

General Information

• Speaker size: 20 cm (8 inches)

• Type: Passive slim subwoofer

• RMS Power Handling: 250 watts

• Maximum power handling: 500 watts

• Voice coil diameter: 50 mm

• Voice coil winding height: 28 mm (according to the D2 data sheet)

• Diaphragm material: fiberglass composite

• Bead material: Rubber

• Basket material: Steel

• Magnet: Double magnet, 40 oz

• Diaphragm area (Sd): 214 cm²

• Sensitivity (SPL): 83 dB (1 W/1 m)

• Maximum linear stroke: ±10 mm (according to the D2 data sheet)

• Maximum mechanical deflection: ±15 mm
  
  

Dimensions

• Outer diameter: 214 mm

• Installation diameter: 182 mm

• Installation depth: 78 mm
  
  

Technical Specifications for ZST8D2 – Dual 2 Ohms

• Impedance: 2 × 2 ohms

• Parallel connection: 1 ohm

• Series connection: 4 ohms

• DC resistance (Re): 2 × 1.8 ohms

• Resonance frequency (Fs): 37.4 Hz

• Mechanical Grade (Qms): 7.04

• Electrical quality (Qes): 0.60

• Overall Quality (Qts): 0.56

• Equivalent air volume (Vas): 10.6 liters

• Moving mass (Mms): 110 g

• Voice coil inductance (Le): 2.18 mH (according to the D2 datasheet)
  
  

Technical Specifications for ZST8D4 – Dual 4 Ohms

• Impedance: 2 × 4 ohms

• Parallel connection: 2 ohms

• Series connection: 8 ohms

• DC resistance (Re): 2 × 3.6 ohms

• Resonance frequency (Fs): 40.7 Hz

• Mechanical Quality (Qms): 5.46

• Electrical Quality (Qes): 0.67

• Overall Quality (Qts): 0.59

• Equivalent air volume (Vas): 10.1 liters

• Moving mass (Mms): 97.5 g
  
  

Recommended case for both versions

• Sealed housing: 9–15 liters

• Bass-reflex enclosure: 20 liters

• Bass reflex tuning frequency (Fb): 39 Hz

• Lower cutoff frequency at −3 dB (F3), bass reflex: 32 Hz

• Bass reflex port diameter: 70 mm

• Bass reflex port cross-sectional area: 38 cm²

• Bass reflex tube length: 31 cm